566 COLLECTED STUDIES IN IMMUNITY. 



We were also able to readily confirm Bordet's statement that the 

 antiamboceptor action is easily inhibited by normal rabbit serum, 

 Naturally the normal amboceptors, whose complementophile groups 

 excited the production of the antiamboceptor, will combine with 

 this antiamboceptor and so be able to deflect it from the amboceptor 

 acting in the given case. Since we regard the antiamboceptor in 

 the sense of a complementoid, this phenomenon corresponds in prin^ 

 ciple to that* described by Neisser and Wechsberg as deflection of 

 complement. 1 



The entire complex of phenomena just discussed shows most 

 strikingly that our assumption harmonizes best with the observed 

 facts. We assume that in Bordet's antiamboceptors we are dealing 

 with antibodies directed against the complementophile groups. The 

 existence of such antiamboceptors again demonstrates that the 

 amboceptor theory is correct. According to Bordet's sensitization 

 theory only such antiamboceptors are conceivable which prevent 

 the amboceptor's union with the cell. But if there are other kinds 

 of antiamboceptors, as the findings just discussed show, we must 

 assume that the amboceptor has other affinities besides those for the 

 cell, and this leads us at once to the conception which we have 

 defined under the name amboceptor. The sensitization theory must 

 therefore be abandoned. 



The next question which arises is whether or not it is possible 

 by means of immunization with amboceptors to produce antiambo- 



this, to effect an inhibition of haemolysis by subsequently adding antiambo- 

 ceptor. It seems to us that this simplified procedure is more convincing, for 

 it will hardly be claimed that the guinea-pig serum is a better suspending medium 

 than physiological salt solution, and that it therefore, in contrast to the latter, 

 leaves the blood-cells intact. Furthermore, inactive guinea-pig serum itself 

 inhibits the hasmolysis of ox blood by amboceptor and complement (guinea- 

 pig). Hence when guinea-pig serum is present the question whether the ab- 

 sence of haemolysis is due to an antiamboceptor or not is left undecided. 



1 In contrast to Bordet, however, we were unable by means of normal ambo- 

 ceptor to effect the subsequent breaking of the union between antiamboceptor 

 and sensitized blood-cells. It may be that in our case the union between anti- 

 amboceptor and sensitized cells so rapidly became firm that it could no longer 

 be dissolved by the normal amboceptor. Even Bordet admits that this dis- 

 solution can be effected only for a certain period, and that then the union 

 becomes very firm. We are pleased to note that Bordet accepts this conception 

 of a gradual tightening of the union of these substances, a conception of the 

 highest importance in the study of immunity reactions. 



